Functional Incisal Edges: Managing the Incisal Guidance

As a member of the Spear Resident Faculty, I have the privilege and the honor to interact with many young dentists seeking to improve their knowledge and skills. I often have requests from dentists to review their cases and provide guidance and direction. Sometimes the requests are for help in treatment planning new cases.

In these circumstances, the objective is to provide suggestions for restorative materials, tooth preparation or designing occlusion and function. Other times the requests are for evaluation of cases in progress or review of cases recently finished. The dentist will send me a finished case and would like to have some constructive feedback on the outcome for learning and growth.

I have seen the work of some tremendous young clinicians who are raising their own bars for clinical knowledge and skill. Reaching out to more experienced dentists and mentors for help, guidance, direction and support is a wonderful way learn and provides increased confidence in tackling larger and more complex cases.

Recently I received an email from Adam, one of my former Loyola University Chicago general practice residents who is now practicing in North Carolina. Adam has kept in touch with me over that past few years by sending me a few of his cases for review. I have seen exceptional growth from him, as he continues to gain experience and confidence. I am very proud of his accomplishments.

Adam has graciously consented to let me use one of his recent cases as an example for this article about functional incisal guidance. Thank you, Adam, for your willingness to share your work!

Adam is a student of Spear Education. Over the last few years, he has participated in numerous Spear Seminars and Workshops. He is also a member of Spear Online. He continues to integrate concepts of Facially Generated Treatment Planning and occlusion into the treatment of his cases.

Adam had just finished Brett’s case and requested that I provide some feedback around the outcome they had created together. Figure 1 is a pre-treatment image of Brett, who wanted to improve his smile and lengthen his teeth. He felt that his upper teeth were short. He did not like the composite restorations that had been previously placed on the facial surfaces of his anterior teeth.

Brett also had older fillings that needed repair and restoration. When he was younger, Brett was interested in phasing his treatment over the next few years to improve his esthetic and functional oral health. Adam and Brett decided that restoring the anterior teeth would be his first phase.

As one of his first extensive veneer cases, Adam did a wonderful job in the restoration of Brett’s anterior teeth! The ceramic has a beautiful shade and texture. There is good marginal integrity and the restoration contours are a good fit for this patient. Brett was very pleased with the esthetic outcome of longer teeth and an improved smile.

For any dentist, there is significant excitement around restoring your first significant veneer case. Establishing the esthetic outcome of shade, shape and smile line can create “tunnel vision” around the veneer restorations. With the primary focus is on the upper restorations, it is easy to forget to pay attention to the opposing teeth and the dynamic interaction they have in function and mastication.

As I examined the post-treatment photo, I noticed a significant difference between the incisal edges of the upper ceramic and the corresponding lower incisors. The incisal edges of the lower anterior teeth are worn flat and have sharp facets at the facial-incisal and lingual-incisal surfaces. The new maxillary ceramic edges are smooth with refined contours.

This disparity is very concerning relative to the expected longevity of the restoration. The mismatch between the new restorations and the preexisting worn tooth surfaces can lead to porcelain fracture. It is very important to not overlook the need for calibrating and adjusting the functional relationship of the new porcelain to the pre-existing opposing natural teeth.

I will use my patient Garret as an example of incisal edge wear calibration and porcelain restoration. Garret presented to my office with worn incisal edges and a desire to restore the upper tooth length and appearance. He was a healthy 21-year-old and had just finished college.

The treatment plan was to restore Garret’s six upper anterior teeth. Orthodontics were ruled out and he wanted to maintain his existing tooth diastemas.

Garret has a habit of moving into crossover tooth position at multiple times during the day and night. This habitual positioning contributed to his worn incisal edges. Restoration of the upper tooth wear with porcelain will not prevent Garret from crossing over in the future.

For the restorations to be successful, there must be correction and adjustment of the opposing lower incisal edges in order to accommodate this lateral mandibular positioning.

Garret was restored with e.max ceramic veneers on his upper six anterior teeth. He was equilibrated to centric relation occlusion. Composite was applied to the lower anterior teeth to level the edges. Garret was pleased with the appearance of his smile and the new incisal edges.

The critical aspect related to the success of this case was to allow Garret to move into a mandibular crossover position and maintain smooth and flat contact between the opposing teeth. Garret moves extensively to both the right and the left.

This case is now nine years old and there has been no fracture of porcelain or composite since the restorations were placed. Garret routinely wears an upper full arch night guard appliance to aid in protection of the porcelain restorations.

I informed Adam of the incisal edge mismatch I had observed in Brett’s case. Adam immediately recalled Brett for incisal edge adjustment to improve the functional relationship between the new porcelain veneers and the lower natural teeth.

Adam was grateful for my feedback and, to date, there has not been an issue with Brett’s restorations. This learning experience will provide Adam with improved awareness and understanding of mandibular function and the importance of incisal edge relationships.

This case is a great example of the importance of mentorship as a crucial role in developmental learning.

I encourage all young dentists to search out a mentor and be open to the guidance, support and encouragement that can develop from that relationship. Adam, thank you again for sharing your case as a learning tool for others at Spear Education.

Jeffrey Bonk, D.D.S., is a member of Spear Resident Faculty.